HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 292/5/E1378    most recent 00698.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (31) Citing Articles via Google Scholar Google Scholar Articles by Potenza, M. A. Articles by Montagnani, M. Search for Related Content PubMed PubMed Citation Articles by Potenza, M. A. Articles by Montagnani, M.

EGCG, a green tea polyphenol, improves endothelial function and insulin sensitivity, reduces blood pressure, and protects against myocardial I/R injury in SHR

Departments of ¹Pharmacology and Human Physiology and ²Emergency and Organ Transplantation, Medical School, University of Bari, 70124 Bari, Italy; and ³Diabetes Unit, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, Maryland

Submitted 20 December 2006 ; accepted in final form 11 January 2007

Epigallocatechin gallate (EGCG), a bioactive polyphenol in green tea, may augment metabolic and vascular actions of insulin. Therefore, we investigated effects of EGCG treatment to simultaneously improve cardiovascular and metabolic function in spontaneously hypertensive rats (SHR; model of metabolic syndrome with hypertension, insulin resistance, and overweight). In acute studies, EGCG (1–100 µM) elicited dose-dependent vasodilation in mesenteric vascular beds (MVB) isolated from SHR ex vivo that was inhibitable by N-nitro-L-arginine methyl ester (L-NAME; nitric oxide synthase antagonist) or wortmannin [phosphatidylinositol (PI) 3-kinase inhibitor]. In chronic studies, 9-wk-old SHR were treated by gavage for 3 wk with EGCG (200 mg·kg^–1·day^–1), enalapril (30 mg·kg^–1·day^–1), or vehicle. A separate group of SHR receiving L-NAME (80 mg/l in drinking water) was treated for 3 wk with either EGCG or vehicle. Vasodilator actions of insulin were significantly improved in MVB from EGCG- or enalapril-treated SHR (when compared with vehicle-treated SHR). Both EGCG and enalapril therapy significantly lowered systolic blood pressure (SBP) in SHR. EGCG therapy of SHR significantly reduced infarct size and improved cardiac function in Langendorff-perfused hearts exposed to ischemia-reperfusion (I/R) injury. In SHR given L-NAME, beneficial effects of EGCG on SBP and I/R were not observed. Both enalapril and EGCG treatment of SHR improved insulin sensitivity and raised plasma adiponectin levels. We conclude that acute actions of EGCG to stimulate production of nitric oxide from endothelium using PI 3-kinase-dependent pathways may explain, in part, beneficial effects of EGCG therapy to simultaneously improve metabolic and cardiovascular pathophysiology in SHR. These findings may be relevant to understanding potential benefits of green tea consumption in patients with the metabolic syndrome.

epigallocatechin gallate; insulin resistance; endothelial dysfunction; nitric oxide; metabolic syndrome; spontaneously hypertensive rats; ischemia-reperfusion

This article has been cited by other articles:

				R. Muniyappa, H. Chen, R. H. Muzumdar, F. H. Einstein, X. Yan, L. Q. Yue, N. Barzilai, and M. J. Quon Comparison between surrogate indexes of insulin sensitivity/resistance and hyperinsulinemic euglycemic clamp estimates in rats Am J Physiol Endocrinol Metab, November 1, 2009; 297(5): E1023 - E1029. [Abstract] [Full Text] [PDF]

				G. Petrosillo, G. Colantuono, N. Moro, F. M. Ruggiero, E. Tiravanti, N. Di Venosa, T. Fiore, and G. Paradies Melatonin protects against heart ischemia-reperfusion injury by inhibiting mitochondrial permeability transition pore opening Am J Physiol Heart Circ Physiol, October 1, 2009; 297(4): H1487 - H1493. [Abstract] [Full Text] [PDF]

				M. A. Potenza, F. Addabbo, and M. Montagnani Vascular actions of insulin with implications for endothelial dysfunction Am J Physiol Endocrinol Metab, September 1, 2009; 297(3): E568 - E577. [Abstract] [Full Text] [PDF]

				M. A. Potenza, S. Gagliardi, L. De Benedictis, A. Zigrino, E. Tiravanti, G. Colantuono, A. Federici, L. Lorusso, V. Benagiano, M. J. Quon, et al. Treatment of spontaneously hypertensive rats with rosiglitazone ameliorates cardiovascular pathophysiology via antioxidant mechanisms in the vasculature Am J Physiol Endocrinol Metab, September 1, 2009; 297(3): E685 - E694. [Abstract] [Full Text] [PDF]

				P. D. B. Ribaldo, D. S. Souza, S. K. Biswas, K. Block, J. M. Lopes de Faria, and J. B. Lopes de Faria Green tea (Camellia sinensis) Attenuates Nephropathy by Downregulating Nox4 NADPH Oxidase in Diabetic Spontaneously Hypertensive Rats J. Nutr., January 1, 2009; 139(1): 96 - 100. [Abstract] [Full Text] [PDF]

				R. Muniyappa, G. Hall, T. L Kolodziej, R. J Karne, S. K Crandon, and M. J Quon Cocoa consumption for 2 wk enhances insulin-mediated vasodilatation without improving blood pressure or insulin resistance in essential hypertension Am. J. Clinical Nutrition, December 1, 2008; 88(6): 1685 - 1696. [Abstract] [Full Text] [PDF]

				N. Tanabe, H. Suzuki, Y. Aizawa, and N. Seki Consumption of green and roasted teas and the risk of stroke incidence: results from the Tokamachi-Nakasato cohort study in Japan Int. J. Epidemiol., October 1, 2008; 37(5): 1030 - 1040. [Abstract] [Full Text] [PDF]

				M. Bose, J. D. Lambert, J. Ju, K. R. Reuhl, S. A. Shapses, and C. S. Yang The Major Green Tea Polyphenol, (-)-Epigallocatechin-3-Gallate, Inhibits Obesity, Metabolic Syndrome, and Fatty Liver Disease in High-Fat-Fed Mice J. Nutr., September 1, 2008; 138(9): 1677 - 1683. [Abstract] [Full Text] [PDF]

				P. A. Davis, M. Jenab, J. P. Vanden Heuvel, T. Furlong, and S. Taylor Tree Nut and Peanut Consumption in Relation to Chronic and Metabolic Diseases Including Allergy J. Nutr., September 1, 2008; 138(9): 1757S - 1762S. [Abstract] [Full Text] [PDF]

				M. C Venables, C. J Hulston, H. R Cox, and A. E Jeukendrup Green tea extract ingestion, fat oxidation, and glucose tolerance in healthy humans Am. J. Clinical Nutrition, March 1, 2008; 87(3): 778 - 784. [Abstract] [Full Text] [PDF]

				S. Lee, R. Muniyappa, X. Yan, H. Chen, L. Q. Yue, E.-G. Hong, J. K. Kim, and M. J. Quon Comparison between surrogate indexes of insulin sensitivity and resistance and hyperinsulinemic euglycemic clamp estimates in mice Am J Physiol Endocrinol Metab, February 1, 2008; 294(2): E261 - E270. [Abstract] [Full Text] [PDF]

				Q. F. Collins, H.-Y. Liu, J. Pi, Z. Liu, M. J. Quon, and W. Cao Epigallocatechin-3-gallate (EGCG), A Green Tea Polyphenol, Suppresses Hepatic Gluconeogenesis through 5'-AMP-activated Protein Kinase J. Biol. Chem., October 12, 2007; 282(41): 30143 - 30149. [Abstract] [Full Text] [PDF]

				S. Wolfram Effects of Green Tea and EGCG on Cardiovascular and Metabolic Health J. Am. Coll. Nutr., August 1, 2007; 26(4): 373S - 388S. [Abstract] [Full Text] [PDF]

				G. E. Mann, D. J. Rowlands, F. Y.L. Li, P. de Winter, and R. C.M. Siow Activation of endothelial nitric oxide synthase by dietary isoflavones: Role of NO in Nrf2-mediated antioxidant gene expression Cardiovasc Res, July 15, 2007; 75(2): 261 - 274. [Abstract] [Full Text] [PDF]